My cat grew up with no dogs, yet when I mention to her that I am possibly getting a dog in the future, she gives me "the look" and won't let me pet her. I know she is not stupid, but how would she know what a dog is?
I'm sure cats can understand the general meaning of what you are saying from the tone of your voice, i.e whether you are angry, happy etc. I don't know if she would understand exactly what you were saying, although cats can learn to associate certain words with the meanings (like 'food' or their names). I know a dog who goes mad whenever someone says 'cat', 'kitty' or 'puss' so maybe your cat has made the association?!